BBC News summed up "Nine Things About Sleep".

1. It is very important to get enough sleep every night.

People who sleep too much or too little are more likely to get sick and live shorter lives. Adults sleep about 6-8 hours a day, newborns sleep about 18 hours a day, and teenagers should ensure 10 hours of sleep. Sleep time varies from person to person. For example, former British Prime Minister Margaret Thatcher only needs to sleep for four hours every night.

2. Less sleep and more diseases.

Lack of sleep is closely related to diabetes, hypertension, cardiovascular diseases, coronary heart disease and obesity, and it will also lead to the decline of human immunity and make people more susceptible to infection. Long-term lack of sleep will also affect brain function and increase the risk of dementia. Studies have found that people who don't get enough sleep are three times more likely to catch a cold than those who get enough sleep.

3. Physical repair requires different stages of sleep.

The first stage is between waking and sleeping, which is a state of relaxation, with slow breathing, relaxed muscles and slow heart rate; The second stage is a deep sleep state, feeling awake, but actually asleep; The third stage is a deep sleep stage, which makes it difficult to wake up and the body is the least active.

4. People who work at night lack sleep and take more sick leave.

Studies have found that night shift workers are more likely to suffer from diabetes and obesity. A new survey in Britain found that night shift workers obviously felt worse health and called in sick more frequently.

5. Women are more likely to lack sleep than men.

A study involving 2000 people in Britain found that sleep problems vary greatly with age and gender, and it is more difficult for women to get enough sleep than men. Especially after giving birth, women are under the double pressure of children and work, and they are more likely to get insufficient sleep.

6. Electronic devices affect teenagers' sleep.

A British survey found that half of children's sleep time is not up to standard. The reasons include that there are too many distractions in the bedroom, such as mobile phones, computers and televisions. The blue light of electronic devices can make people feel sleepy and make the brain more excited. It is recommended to close 90 minutes before going to bed.

7. Sleep disorders such as insomnia are increasing.

The British survey found that in the past 10 years, the number of people who had difficulty seeking medical treatment due to sleep increased greatly. There are many kinds of sleep-related disorders, and the biggest problem is the significant increase in the incidence of obesity. In addition, insomnia is becoming more and more serious.

8. Social activities have a greater impact on sleep.

A study involving people's sleep habits in 20 developed countries found that social activities such as commuting, school hours and leisure habits have far greater influence on sleep than circadian rhythm.

9. Lights make people sleep later.

Lighting will aggravate the difference between morning and night owls, especially "night owls" who will sleep later. Therefore, people who like to sleep late and get up late, it is best to reduce the light time at night and increase the natural sunshine time during the day, so that the biological clock is closer to the natural rhythm.